Fuse tube adapter



A. G. STEINMAYER FUSE TUBE ADAPTER Filed Aug. 7, 1946 Fica. Z

IKO'

INVENTOR.

ALwm G. STUNMAYER ATTQRNEY Patented Oct. 18, 1949 FUSE TUBE ADAPTER Alwin G. Steinmayer, Milwaukee, Wis., assignor to Line Material Company, Milwaukee, Wis., a

corporation of Delaware Application August 7, 1946, Serial No. 688,815

2 Claims. (Cl. 20o-120) This invention relates to a fuse tube adapter.

It is a well known fact that large capacity fuse tubes must, of necessity, have a large bore in order to accommodate the fusible element and leader and also to provide the necessary rupturing capacity.

It frequently happens that purchasers When they first install the fuse tubes on their distribution lines, do not need the large rcapacity fuse tubes, but they anticipate subsequent developments, which would necessitate the large fuse tube with the high rupturing capacity. If on the one hand they install small fuse tubes for low rupturing capacities, they would have to discard this equipment and install larger fuse tube assemblies when their customers had increased in number. On the other hand, if they install large fuse tubes,with high rupturing capacities and used small fuse links with these fuse tubes, they would run the danger of failing to build up a suiiicient compression in the tube to rapidly extinguish the arc and the arcingtime might be sufficiently long to cause total destruction of the fuse tube and the associated parts.

This invention is designed to provide a fuse tube adapter which will permit the initial purchase and installation of large capacity fuse tubes but which when placed within such large capacity fuse tubes will alter the action of the fuse tube so that it may be used with small capacity fuse links with the assurance that the fuse tube will completely and quickly clear itself on overload.

Further objects are to provide a Very simple type of fuse tube adapter which is cheap to make and which is easily installed in a large capacity fuse tube, and which is so constructed that it will take a simple type of fuse link or a fuse link provided with a small permanently installed iber or other tube, and which is so made that if an abnormally large overload occurred and the adapter itself is ruptured, no damage will be caused to the main fuse tube assembly as this large overload would generate sufficient compression to quickly extinguish any arc that might be formed.

An embodiment of the invention is shown in the accompanying drawings, in which- Figure 1 is a fragmentary view partly in section showing the adapter in place.

Figure 2 is an enlarged fragmentary view of a section of the upper portion of the structure shown in Figure 1.

Referring to the drawings, it'will be seen that a standard type of drop-out fuse assembly has been shown although the adapter is applicable for use in any type of fuse tube, whether of the drop-out kind or of some other type. The main fuse tube illustrated in the drawings, may be similar to that disclosed in the patent to Schultz andSteinmayer, No, 2,176,227 of October 17, 1939, for Combined switch and fuse, assigned to the assignee of the present application. This fuse tube is indicated by the reference character I and may be of relatively high rupturing capacity With a relatively large internal bore. It is provided with an upper terminal 2 and a lower terminal assembly indicated generally at 3 against which the upper lbrush contact 4 and the lower brush contact 5 respectively bear. The fuse link may comprise any type of link construction. In the form chosen for illustration, the fuse link comprises a fusible section 6 and a strain Wire 1, which are joined at their upper ends through the member 8 to a buttonhead 9 and at their lower ends to a flexible leader I 0. The fuse link also preferably, though not necessarily, may have a small ber tube I I formed as a unitary part of the fuse link assembly. This construction is similar to one of the forms of the invention shown in the patent to Brown, No. 2,382,602 of August 14, 1945, for Fuse link, assigned to the assignee of this application.

It is customary to provide a washer I2 which loosely receives the shank I3 of the buttonhead 9. The buttonhead 9 is clamped in place by means of the screw cap I 4 forming a portion of the upper terminal of the fuse tube assembly. The flexible leader I0 extends downwardly through the open lower end of the expulsion fuse tube I and is attached to a supporting lever I5 pivoted as indicated at I6 on the member I'I rigid with the fuse tube I. The lower end of the lever I5 is provided with trunnions, not shown, pivoted in the lower stationary terminal I9 as shown particularly in the Schultz et al patent hereinabove referred to. As stated, any other type of fuse tube assembly, provided it is an expulsion type, can be used.

The adapter comprises a tube 2i) of insulating material, preferably of iiber, whose end is received in an upper metal iitting 2l, which is crimped or otherwise rmly secured to the tube 20. This upper tting or Contact member 2l is provided with an upper flange 22 which rests in place upon the upper terminal 2 and which supports the washer I2 of the buttonhead S of the 'fuse link. The fiber tube 20 extends only part way downwardly within the main fuse tube I as particularly shown in Figure 2. As a specie example, though the invention is not limited to these values, the interior bore of the adapter tube may be of such a size as is customarily used with a 50 ampere fuse link, Whereas the interior bore of the main tube I may be of a value customarily used with a 200 ampere fuse link.

In practicing the invention, assuming that the purchaser has installed a large rupturing capacity main fuse tube I to take care of anticipated increases in the load on the distribution line but Wishes to use a relatively smaller capacity fuse link, he merely places the adapter 2B in the upper end of the fuse tube I. A small size fuse link is threaded through the adapter and the main fuse tube I and the cap I 4 of the main fuse tube is screwed into place. The cap I4 not only clamps the buttonhead of the fuse link, but also clamps the adapter in place.

It is obvious that if any overload oi about the normal capacity of the fuse link occurs, the vmultiple tube construction Will readily clear itself as sufficient com-pression will build up within the adapter 20 to insure proper ejection of the vremaining portion of the fuse link and quick extinction `of the arc. If a small overload ocfcurs With the particular type of fuse link employed, the vsmall ber tube Il of the fuse link assembly Will insure building up of proper compression Within the small iiber tube II itself to .insure extinction of the arc and proper ejection of Vany remaining portion of the fuse link.

On the other hand, if any abnormally large overload occurred, of such a value that it might rupture the adapter .20 and most certainly rupture the small ber tube Il, no damage would result as suilicient compression would build up .in .the main fuse tube I to insure extinction of the arc and ejection of any remaining portion of the fuse link.

Thus it will be seen that a multiple fuse tube yconstruction yhas been provided which will proper- .ly function for overloads of Widely different values from a relatively small overload to a relatively heavy overload far in excess of any for which the particular fuse link is intended Without .any damage to any part of the main fuse tube assembly itself.

Further than this, the adapter is a relatively inexpensive member cheaplyproduced and easily installed and it is of practically no consequence so far as expense is concerned to discard all of the adapters on a distribution line or such of .them as is necessary, when the development supplied by the distribution line has increased to such a value that the large capacity fuse link may now be employed. Thus it is possible for a customer to initially install large capacity fuse tube assemblies on his distribution line and con- .tinue to use these although the load on the line does not at the time of installation Warrant such large size fuse tube assemblies. On the other hand, when the load on the line has developed to a point sufficient to Warrant the use of the CII large rupturing capacity installation, the adapters are merely discarded with very minor eX- pense to the customer and the large size fuse links are used. Ordinarily, it is intended that the adapter be used over and over, the ruptured fuse alone being replaced.

Although this invention has been described in considerable detail, it is to be understood that such description is intended as illustrative rather than limiting, as the invention may be variously embodied and is to be interpreted as claimed.

I claim:

l. A fuse tube assembly comprising a main outer insulating tube open at both ends and having a terminal provided with a closure cap for closing one end of said main tube, an inner insulating tube open at both ends and constituting an adapter located Within said main tube and having va ange at one end adjacent the closure cap and arranged to be supported solely from the terminal of said main tube and clamped in place by said closure cap, and a fuse link having an enlarged head free from attachment to said innei` tube and arranged `to be clamped between the flange of said inner tube and the closure cap of said main tube and having a fusible section located rwithin Asaid inner tube and a flexible leader extending from the fusible section outwardly through both ysaid main and inner tubes.

2. A fuse tube rassembly comprising a main outer insulating tube open at vboth ends and having a terminal provided With a closure cap for closing one end of said main tube, an inner insulating tube open 'at both ends and constituting an adapter located Within said main tube and having a flange at one end adjacent the closure cap and arranged to be supported solely from the terminal of said main tube and clamped in place by said closure cap, and a ruse link assembly having an enlarged head free from attachment to said inner tube and arranged to be clamped between the flange of `said inner tube and the closure cap of said main tube and having a fusible section located Within said inner tube and a flexible leader extending from the Vfusible section outwardly through both said main and inner tube, said fuse link assembly having an insulating tube surrounding the fusible section and located within said inner tube.

ALWIN G. STEINMAYER.

REFERENCES CITED lThe following references are of file of this patent:

UNITED STATES PATENTS record in the 

